WASHINGTON—Oregon Sen. Ron Wyden defended his state's first-in-the-nation assisted suicide law last week at a Senate hearing — the first since the Supreme Court upheld Oregon's law in January.

Sen. Sam Brownback, a Kansas Republican who is considering a run for president, called the hearing to explore what he called the "unintended consequences and slippery slope of doctor-assisted suicide."

Brownback, who opposes assisted suicide, said he does not expect to introduce legislation this year, but is concerned that the Supreme Court ruling undermined "the culture of life" in the United States.

"When the law permits killing as a 'medical treatment,' society's moral guidelines are blurred," said Brownback, chair of a Senate Judiciary subcommittee on the Constitution and civil rights.

In the United States, assisted suicide laws "could actually create a financial incentive for insurance companies to encourage prematurely ending the lives of those who need long-term care," Brownback said.

Wyden and other backers of the law disputed that, saying Oregon has been careful to install safeguards that regulate how and when prescriptions can be written and require that patients administer the lethal dose themselves.

Advocates cited a report by Oregon health officials showing that just 246 terminally ill patients have used the law to end their lives since the measure took effect in 1998 — an average of just 31 per year.

The total number of deaths under the law reflects a tiny portion of the state's average 31,000 annual deaths, according to the Oregon Department of Human Services.

But Brownback cited the "ominous" experience of the Netherlands, where legalized doctor-assisted suicide has led to what he called "involuntary euthanasia," and said he suspected the numbers in Oregon would rise over time.

Wyden, a Democrat, said he personally opposes assisted suicide and twice voted against it in state ballot measures — in part because of concerns that the measure could be used disproportionately by the poor elderly.

"While I do not know how I would vote if the issue were to appear on the Oregon ballot once more, I believe it is time for me to acknowledge that my fears concerning the poor elderly were, thankfully, never realized," Wyden said. "The law has not been abused."

Ann Jackson, CEO of the Oregon Hospice Association, said the assisted suicide law — and the extensive debate over it for more than a decade — has helped make Oregon a leader in end-of-life care.

Oregon's hospital death rate is the lowest in the nation, she said, and its home death rate is among the highest, along with Utah. One explanation for the low rate of assisted suicides "may be the high quality of hospice and palliative care provided in Oregon," she said.

Palliative care, sometimes called comfort care, is aimed at making a terminally ill patient more comfortable in the face of sometimes extreme pain.

Instead of trying to repeal Oregon's law, Congress should work to advance pain management and hospice care,Jacksontold Brownback.

But Diane Coleman, president of "Not Dead Yet," a disability rights group that opposes assisted suicide, said members of her group fear that doctors will undervalue the disabled as they consider whether to recommend assisted suicide to their patients.

"What looks to some like a choice to die begins to look more like a duty to die to many disability activists," she said. Coleman and other opponents questioned the Oregon statistics on assisted suicide, noting they are based on self-reporting by doctors — "who are about as likely to tell the state they violate the law as they are to tell the IRS they cheated on their taxes," said Wesley Smith, a senior fellow at the Seattle-based Discovery Institute.

Brownback said he was concerned about the message the Oregon law sends and the possible consequences as assisted suicide becomes more and more accepted.

"I know you'd like (assisted suicide) to be safe, legal and rare," he told advocates, "but the trend lines don't go that way. These things tend to expand."

Wyden, as he has in the past, vowed to block any attempt by Brownback or any other lawmaker to repeal the Oregon law.